#ifndef VEC3H
#define VEC3H

#include <math.h>
#include <stdlib.h>
#include <iostream>

class vec3
{
public:
    vec3(){}
    vec3(float e0, float e1, float e2)
    {
        e[0] = e0;
        e[1] = e1;
        e[2] = e2;
    }
    inline float x() const { return e[0]; }
    inline float y() const { return e[1]; }
    inline float z() const { return e[2]; }

    inline float r() const { return e[0]; }
    inline float g() const { return e[1]; }
    inline float b() const { return e[2]; }

    inline const vec3& operator+() const { return *this; }
    inline vec3 operator-() const { return vec3(-e[0], -e[1], -e[2]); }
    inline float operator[](int i) const { return e[i]; }
    inline float& operator[](int i) { return e[i]; }

    inline vec3& operator+=(const vec3 &v2)
    {
        e[0] += v2.e[0];
        e[1] += v2.e[1];
        e[2] += v2.e[2];
        return *this;
    }

    inline vec3& operator-=(const vec3 &v2)
    {
        e[0] -= v2.e[0];
        e[1] -= v2.e[1];
        e[2] -= v2.e[2];
        return *this;
    }

    inline vec3& operator*=(const vec3 &v2)
    {
        e[0] *= v2.e[0];
        e[1] *= v2.e[1];
        e[2] *= v2.e[2];
        return *this;
    }

    inline vec3& operator/=(const vec3 &v2)
    {
        e[0] /= v2.e[0];
        e[1] /= v2.e[1];
        e[2] /= v2.e[2];
        return *this;
    }

    inline vec3& operator*=(const float t)
    {
        e[0] *= t;
        e[1] *= t;
        e[2] *= t;
        return *this;
    }

    inline vec3& operator/=(const float t)
    {
        e[0] /= t;
        e[1] /= t;
        e[2] /= t;
        return *this;
    }

    inline float length() const { return std::sqrt(e[0] * e[0] + e[1] * e[1] + e[2] * e[2]);}
    inline float squared_length() const { return (e[0] * e[0] + e[1] * e[1] + e[2] * e[2]); }

    inline void make_unit_vector()
    {
        float len = length();
        e[0] /= len;
        e[1] /= len;
        e[2] /= len;
    }

    float e[3];
};

inline vec3 operator+(const vec3 &v1, const vec3 &v2)
{
    return vec3(v1.e[0] + v2.e[0], v1.e[1] + v2.e[1], v1.e[2] + v2.e[2]);
}

inline vec3 operator-(const vec3 &v1, const vec3 &v2)
{
    return vec3(v1.e[0] - v2.e[0], v1.e[1] - v2.e[1], v1.e[2] - v2.e[2]);
}

inline vec3 operator*(const vec3 &v1, const vec3 &v2)
{
    return vec3(v1.e[0] * v2.e[0], v1.e[1] * v2.e[1], v1.e[2] * v2.e[2]);
}

inline vec3 operator*(const vec3 &v1, float t)
{
    return vec3(v1.e[0] * t, v1.e[1] * t, v1.e[2] * t);
}

inline vec3 operator*(float t, const vec3 &v1)
{
    return vec3(v1.e[0] * t, v1.e[1] * t, v1.e[2] * t);
}

inline vec3 operator/(const vec3 &v1, const vec3 &v2)
{
    return vec3(v1.e[0] / v2.e[0], v1.e[1] / v2.e[1], v1.e[2] / v2.e[2]);
}

inline vec3 operator/(const vec3 &v1, float t)
{
    return vec3(v1.e[0] / t, v1.e[1] / t, v1.e[2] / t);
}

inline float dot(const vec3 &v1, const vec3 &v2)
{
    return v1.e[0] * v2.e[0] + v1.e[1] * v2.e[1] + v1.e[2] * v2.e[2];
}

inline vec3 cross(const vec3 &v1, const vec3 &v2)
{
    return vec3(
        (v1.e[1]*v2.e[2]-v1.e[2]*v2.e[1]),
        (-(v1.e[0]*v2.e[2] - v1.e[2]*v2.e[0])),
        (v1.e[0]*v2.e[1] - v1.e[1]*v2.e[0])
    );
}

inline vec3 unit_vector(vec3 v)
{
    return v / v.length();
}

#endif
